[C++]complex with int type

#include <complex>

#include <iostream>

using namespace std;

int main(void )

{

    complex< int> z(20, 200);

    cout << abs< int>(z) << endl;

    return 0;

}

According to the C++ ISO spec, §26.2/2:

The effect of instantiating the template complex for any type other than float, double or long double is unspecified.